The present invention generally relates to aircraft environmental control systems (ECS), propulsion engines and the bleed air systems that supply the ECS. More particularly, the invention relates to apparatus and methods by which an ECS may be operated with low pressure bleed air so that fuel burn is minimized during flight of an aircraft.
The new generation of commercial aircraft will have to be ever more fuel efficient. Some, maybe most, will remain powered by engines designed for supplying bleed air to the aircraft systems, but may have to offer fuel burn levels competitive with “more electric” bleed-less solutions. It is essential in order to reduce fuel usage by the airplane that the overall impact on the engine of various bleed and power extractions as well as drag requirements for both pressurizing and cooling the cabin be optimized. An energy optimized solution that may allow usage of lower bleed pressure supply from the engines to the ECS and other user systems would offer a competitive alternate to “more electric” ECS architectures with relatively low development risks.
As can be seen, there is a need for an ECS that may be operated with bleed air at lower pressure from a relatively lower energy stage from the engines and thereby providing for reduced fuel burn during flight of an aircraft.